Two Indian tourists killed in a road crash south of Tokoroa yesterday have been named.

They were father and son, Dilip Kataruka, 56, and Madhav Kataruka, 19, from Jharkhand in eastern India.

The two men died after they collided head-on with a truck travelling along State Highway 1, near Atiamuri, about 1pm yesterday.

They had been in the country since December 10, after flying to Auckland to visit relatives.

The cause of the crash is still under investigation.

Meanwhile, the bodies of a family of five, including a newborn, may have lain in the mangled wreckage of their van for up to two nights after it ran off the road and ended up wrapped around a tree.

The wreckage of the late-model blue van was discovered by road workers yesterday afternoon on Whakamaru Rd (SH32), 31 kilometres southwest of Tokoroa.

The family's van was found among pine trees, concealed from the road, about 6km from their home in Whakamaru.

Inside were the bodies of Richard Melling, 37, and driver Lisa Crowley, 23, and their three children, Jordan Melling, 11, Brody Crowley, 2, and a 2 or 3-week-old boy who police believe had yet to be named.

The family were last seen at their home at 8pm on Sunday, and police are unsure when the crash happened.

It appears the vehicle crossed the road on to a steep bank, rolled and smashed into two trees on the edge of a pine plantation.

The wreckage was wrapped around the trunk of the second tree, with the windscreen four metres away in scrub. The impact of the crash dislodged the engine from the chassis, and the damage was so severe that the make and type of the vehicle could not immediately be identified.

Police were still trying to determine the causes of both crashes last night.

Taupo area commander Inspector Steve Bullock said: "Speed, alcohol, inattention and restraints - or lack of thereof - are the No 1 factors that contribute to fatalities on our roads, and we want people to think about all of those things before they get behind the wheel of a vehicle.